Method for producing metal adsorptions.



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- UNITED STATES PATENT OFFICE. I IBOTHO SCHWL F RIN, OF FRANKFORT-ON-THE-MAI N, GERMANY, ASSIGNOR T0 GESELL- SOHAFT FUR. ELEKTRO -OSMOSE IVE-3:13,. OF FRANKFORT-ON-TI-iE-MAIN, GERMANY,

A CORPORATION.

' METHOD r03 rnon'uome METAL ansoarrrons.

No Drawing.

Specification of Letters Patent. Application filed January 4, 1913. Serial No. 740,259.

Patented May 26, 1914.

To all whom it mayconcem:

Be it'known that I, Borrro SCHWERIN, a subject of the German Emperor, and residing at Frankfort-on-the-Main, Germany, have invented certain newand useful Improvements in Methods for Producing Metal Adsorptions, of which the following is a specification.

This invention relates to amethod for producing metal adsorptions (that is to say.

metals adsorbed by some other substance) and consists in causing colloidal suspensions The invention is adapted for the produc-.

tion of cont-a ctsubstances, and for the manufacture of. therapeutic or pharmaceutical preparations. It will be further explained withvreference to some examples.

Finely subdivided substances of the-aforesaid kind are brought into the sol-state under suitable conditions in water-or in another appropriate liquid'. Into this sol-sus- -pension is introduced therequired proportion of metal in the torm'of a solution, for insance a solution of a salt of gold,silver or platinum, and then this solution is subjected to one or other of the many methods of reduction which are suitable for obtaining a colloidal solution of the metal. For in stance,-when a gold adsorption is to be made, sodium or potassium carbonate may be'added and reduction may beefiected by means of.

formaldehyde. The gold in the colloidal condition is adsorbed by the very fine particles of the carrier and forms a violet or blue suspension accordingly as one or other of the known reducing agents has ,been used.

; This suspension is filtered and the filtrate will be found to be completely clear. The

metal is held adsorbed, remarkably firmly, by its carrier. In the case of gold adsorbed by-carborundum for instance, the gold adsorption. may be boiled with acids (except aqua regia) or alkalis without dissolution of the adsorption. The precipitation of platinum on asbestos is aknown operation; the

product, however, is by no mean-s so active a substance as thatwhich can be produced in accordance withthisinvention. The metal cannot be in so active a condition as when it is not only adsorbed bya colloid, but is itself used in a truly colloidal form. Moreover, the present invention produces bodies of greater stability than has hitherto been attainable. r

Metal 'adsorptions 'made in accordance with the invention are so stable that even when heated nearly to the melting point of the metal, the colloidal nature of the latter 1s not lost. This statement can be confirmed by osmotic methods,'the application of which to the metal adsorption which has been heated St. veral times serves to separate the metal in colloidal solution from the burnt substance in a Very finely subdivided condition. The proportion of metal adsorbed depends on'the surface and thepotential of the particles. Since the surface of the suspended particles increases very. much as the degree of their dispersion increases the proportion of mercury. Preparations have also been mate in which for example colloidal silver is made stable by a protective colloid, such as albumen (collargol). The use of albumen has, however, certain disadvantages. If undecomposable,-;finely subdivided substances, which may if necessary be purified by electro-osmose and therefore be pure, are used,

such materials may be caused to adsorb colloidal metals in accordance-with this invention and remarkably active, substances are.

thus. obtained without the disadvantages appertaining to the use of albumen. Amorphous silicic acid is' an example of such a substance; this material when used alone or vmixed with othersubstancesv displays remarkable therapeutic. properties. By the present invention it is possible to adsorb by purified amorphous electrically active silicic acid, colloidal metals and in particular noble metals, and. the preparations thus obtainedhave the advantage that the basis is an undecomposable and harmless substance, which may be completely freed from all harmful admixtures by electro-osmotic purification. Hydrated alumina has like properties. The proportion of the colloidal adsorption can be most accurately determined; the materials are permanent for an unlimited time and undergo no kind of decomposition. Since, according to the present invention it is possible to produce the preparations in the form of powder, the methods of dry treatment which have lately found application for medical purposes can be used with success andthe quantity appliedmay be adjusted Very finely. The possibility of adsorbing liquids and semisolid substances, and also in colloidal suspension.

therapeutic application the tendency to draw out secretions, is. in no way influenced by the pre -sure of the metal in the colloid.

What I claim is:

1. The method of producing metal adsorpt-ions consisting in bringing a metal'into the colloidal state when in the presence of a 

